1. Field of the Invention
The present invention relates to a threading apparatus to be attached to a sewing machine or an embroidering machine to automatically guide a sewing yarn into a needle eye.
2. Prior Art
Manual threading, in itself, is a laborious operation even for young people with good eyesight. It is tremendously laborious for elderly people. Poor lighting on needle eyes makes the threading operation tougher. Needless to say, manual threading for an embroidering machine as shown in FIG. 7 requires more time and energy because many needles are involved.
To ease threading operations, various attempts have been made. Japanese Patent Laid-Open Publication No.7-88276 (FIG. 10, prior art) discloses that a threading apparatus 1 is comprised of:
(1) a needle insertion hole 3 provided vertically in the body 2; PA0 (2) a suction hole 4 intersecting with the needle insertion hole 3; and PA0 (3) a pipe 15 connected to the insertion hole 4 and a suction chamber 20 for threading a yarn into a needle eye by means of sucked air when the needle is in the insertion hole 3. PA0 (1) When a needle is inserted in the needle insertion hole 3, room or gap is left in the insertion hole 3 and unwanted air enters the room. As a result, incoming air weakens the air flow from the suction hole 4, and a yarn may not be properly guided into a small needle eye. PA0 (2) A shallowly inserted needle does not provide air-tight condition in the insertion hole 3, which causes the same problem as described above. On the other hand, if a needle can substantially perfectly fits, leaving no gap in the insertion hole 3, the insertion operation itself will then become extremely hard. The needle can not be properly inserted into a desired position in the suction hole 3 easily. PA0 (3) When a needle is lowered instantly into the insertion hole 3, the tip of the needle will be damaged upon touching the bottom of the insertion hole 3 because the needle is designed to go further down to pick up a bobbin thread. PA0 (4) A threaded yarn will come off a needle if the yarn is caught or tangled during the needle lifting operation. PA0 (a) an air device externally provided for generating reduced pressure; PA0 (b) an air suction pipe connected to the external air device; and PA0 (c) an air path leading to a front portion of the air suction pipe.
The disclosed device above can be used for sewing as well as embroidery lace needles to thread a yarn instantaneously. However, the following technical problems exist.